Hunan is an inland province in Central China. Located in the middle reaches of the Yangtze watershed, it borders the province-level divisions of Hubei to the north, Jiangxi to the east, Guangdong and Guangxi to the south, and Guizhou and Chongqing to the northwest. Its capital and largest city is Changsha, which abuts the Xiang River. Hengyang, Zhuzhou, and Yueyang are among its most populous urban cities.

With a population of just over 66 million as of 2020^[update] residing in an area of approximately 210,000 km² (81,000 sq mi), it is China's 7th-most populous province, the third-most populous among landlocked provinces (after Henan and Sichuan), the third-most populous in South Central China (after Guangdong and Henan), and the second-most populous province in Central China. It is the largest province in South Central China and the fourth-largest landlocked province.

Hunan's nominal GDP was US$747 billion (CN¥5.32 trillion) as of 2024, appearing in the world's top 20 largest sub-national economies, with its GDP (PPP) being over US$1.55 trillion. Hunan is the 9th-largest provincial economy in China, the fourth-largest in South Central China, the third-largest in Central China, and the fourth-largest among landlocked provinces. Its nominal GDP per capita exceeded US$11,405 (CN¥81,225), making it the third-richest province in South Central China, after Guangdong and Hubei. As of 2020, Hunan's nominal GDP reached $605 billion (CN¥4.18 trillion), exceeding that of Poland, with a GDP of US$596 billion, and Thailand, with a GDP of US$501 billion, the 22nd- and 25th-largest in the world, respectively.

The name Hunan literally means "south of the lake". The lake in question is Dongting Lake, in the northeast of the province. Vehicle license plates from Hunan are marked Xiāng (Chinese: 湘), after the Xiang River, which runs from south to north through Hunan and forms part of the province's largest drainage system. The area of Hunan was under Chinese rule as far back as 350 BC. Hunan was the birthplace of communist revolutionary Mao Zedong, who became the Chairman of the Chinese Communist Party and the founding father of the People's Republic of China. Hunan today is home to some ethnic minorities, including the Tujia and Miao, along with the Han Chinese, who make up a majority of the population. Varieties of Chinese spoken include Xiang, Gan, and Southwestern Mandarin.

Wulingyuan was inscribed as a UNESCO World Heritage Site in 1992. Changsha, the capital, is in the eastern part of the province and is an important commercial, manufacturing, and transportation center. The busiest airports serve domestic and international flights for Hunan, including Changsha Huanghua International Airport, Zhangjiajie Hehua International Airport, and Changde Taohuayuan Airport.

Hunan is the seat of the Yuelu Academy (later Hunan University), one of the four major academies over the last 1,000 years in ancient China. As of 2023, Hunan hosted 137 institutions of higher education, ranking fifth among all province-level divisions of China, and it houses five Double First-Class Universities of Hunan, Defense Technology, Central South, Hunan Normal and Xiangtan. As of 2024, two major cities in Hunan (Changsha 23rd and Xiangtan 199th) ranked in the world's top 200 cities by scientific research outputs.

Hunan's primeval forests were first occupied by the ancestors of the modern Miao, Tujia, Dong and Yao peoples. The province entered written Chinese history around 350 BC, when it became part of the Zhou dynasty. After Qin conquered the Chu in 278 BC, the region came under the control of Qin, and then the Changsha Kingdom during the Han dynasty. At this time, and for hundreds of years thereafter, the province was a magnet for settlement of Han Chinese from the north, who displaced and assimilated the original indigenous inhabitants, cleared forests and began farming rice in the valleys and plains. The agricultural colonization of the lowlands was carried out in part by the Han people, who managed river dikes to protect farmland from floods. To this day, many of Hunan's small villages are named after Han families who settled there. Migration from the north was especially prevalent during the Eastern Jin dynasty, Sixteen Kingdoms and the Northern and Southern dynasties periods, when the north was mostly ruled by non-Han ethnic groups (Five Barbarians) and in perpetual disorder.

During the Five Dynasties and Ten Kingdoms period, Hunan was home to its own independent regime, Ma Chu.